This invention relates to an apparatus for preventing a leakage of a portion of a coarse powder into a fine powder side in a classifier for classifying raw material into fine powder and coarse powder.
It is well known for a classifier to have a plurality of rotating vortex adjusting members and a plurality of fixed guide vanes at the outside of the vortex adjusting members in a casing in which a raw material is classified into a coarse powder and a fine powder, to flow and pass the fine powder through a classifying chamber together with the air flow and to discharge and collect the classified powder at the outside of the machine casing by introducing the raw material into the air flow which forms the free vortex at first and then turns into the forced vortex.
However, in such prior classifiers, although the raw material charged into the machine casing from a raw material inlet would be dispersed by the rotation of the horizontal dispersing disc, there still resides the problem in which the non-classified powder not yet sufficiently dispersed by such rotation is mixed into and discharged with the fine powder by being carried on the air flowing into the interior of the classifying chamber, when it doesn't reach appropriate tangential speed and as a result the phenomenon of coarse particles being mixed in with the fine particle portion, that is the phenomenon of the coarse particles leaking into the fine particles can be seen.